Device for determing that an unexposed film is developed by the proper process

ABSTRACT

A device is disclosed which alarms against the inadvertent processing of one film-type by processing solutions compatible with another type of film. A common radiation source, to which the film to be processed is photographically insensitive, shines through both a reference filmstrip and film to be processed, thereby to produce respective signals for comparison purposes. The film to be processed passes over a circumferentially slotted pulley disposed at the entrance to the processing equipment, the radiation source being within the periphery of the pulley; and the off-axis location of the radiation source within the periphery of such pulley permits compactness for the device.

United States Patent 1151 3,639,061 OBrien et al. 5] Feb. 1, 1972 54 DEVICE FOR DETERMING THAT AN 2,631,511 3/1953 Tuttle ..356/203 UNEXPOSED FILM IS DEVELOPED BY THE PROPER PROCESS lnventors: Robert J. OBrien; Norman B. Woodall;

Donald H. Anderson, all of Rochester, N.Y.

Assignee: Eastman Kodak Company, Rochester,

Filed: Mar. 30, 1970 Appl. No.: 23,736

U.S. Cl ..356/72, 95/89 R, 250/219 FR, 356/206 Int. Cl. ..G0ln 21/30 Field of Search ..95/89 R; 356/202, 203, 205, 356/206, 51, 72; 250/219 F References Cited UNITED STATES PATENTS 1/1933 Hunt ..356/72 Primary Examiner-Ronald l... Wibert Assistant ExaminerOrville B. Chew, ll Aztorneywalter O. Hodsdon and Robert F. Cody [5 7] ABSTRACT A device is disclosed which alarms against the inadvertent processing of one film-type by processing solutions compatible with another type of film. A common radiation source, to which the film to be processed is photographically insensitive, shines through both a reference filmstrip and film to be processed, thereby to produce respective signals for comparison purposes. The film to be processed passes over a circumferentially slotted pulley disposed at the entrance to the processing equipment, the radiation source being within the periphery of the pulley; and the off-axis location of the radiation source within the periphery of such pulley permits compactness for the device.

6 Claims, 2 Drawing Figures DEVICE FOR DETERMING THAT AN UNEXPOSED FILM IS DEVELOPED BY THE PROPER PROCESS BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates in general to fault or problem indicators; and in particular provides apparatus useful with photographic film processing equipment to assure against the inadvertent processing of one type of film through a processing solution which is designed for use with another type of film.

2. Description Relative to the Prior Art Proper processing of exposed photographic film requires that such film be passed through developing solutions designed particularly for the film in question. Such processing, and other film handling steps, must be carried out under controlled (dark) lighting conditions. To process film of a given type with incompatible processing solutions results, usually, in such film being ruined. And so, film-processing technicians must constantly be on guard to assure against irreparable damage to the film of a customer by the inadvertent use of the wrong processing procedure for the film in question.

In a typical photofinishing plant, reels of exposed Ektachrome and Kodachrome film are continually being received for processing. The desirable practice is to splice, in the dark, all Ektachrome film together into a continuous web for passage through Ektachrome processing solutions; and to splice, in the dark, all Kodachrome film together into a continuous web for processing through Kodachrome processing solutions. It may occur, however-especially because of the dark in which film handling must take placethat Ektachrome film will be spliced into a web of Kodachrome film, or vice versa, thereby attendantly and irreparably ruining the improperly processed film to the detriment of the film owner, and to the detriment of the good will of the photofinisher.

SUMMARY OF THE INVENTION The invention proposes the use of a device at the input to film-processing equipment to detect, preferably on a continuous basis, whether the film being fed to such equipment, and the processing solutions employed therewith, are compatible; and if not, to alarm or otherwise stop the operation of such equipment, The device of the invention effectively, and continuously, compares a reject reference film strip with the film web entering the processing equipment, whereby as long as the two films are different, the alarm remains unsounded, etc.

To provide such comparison, the invention in its presently preferred form proposes that the film web be passed over an idler pulley disposed at the input to the processing equipment. The pulley is provided with a continuous circumferential slot; and contained within the periphery of the pulley is a source of chopped radiation (usually infrared for Ektachrome- Kodachrome environment). To economize on space, i.e., to assure as small a pulley as possible, and thereby permit apparatus embodying the invention to be fit into most film processing systems, the light source is disposed off the rotary axis of the pulley. A lens inside theperiphery of the pulley focuses the chopped light through the pulley slot to a photodetector via the film web being processed; anda second lens, radially outside the periphery of the pulley, focuses the chopped light which passes through the pulley slot to a second photodetector via the reference film strip. A circuit is provided to compare the respective outputs of the photodetectors, and to indicate when such outputs are dissimilar.

An object of the invention is to provide means for preventing photographic film damage by the inadvertent processing of one film type through and by means of processing solutions designed for another'type offilm.

The invention will be described with reference to the figures, wherein v FIG. 1 is a schematic block diagram illustrating usage of apparatus according to the invention, and

FIG. 2 is a combined sectional view and circuit illustrating apparatus embodying the invention in its presently preferred form.

Referring to FIG. 1, a film-processing system 10 is indicated as having a film web 12 processed through it. At the input of the film-processing system 10, a monitor device 14, such as that proposed by the invention, has the film web passed thereby. A monitor device 14, as will be more fully described below, produces a pair of signalsone with respect to the film web 12, and one with respect to a reject reference film strip 16 thatis incompatible with the processing solutions employed in the system I0and applies such signals to a circuit 18 adapted effectively to compare such signals.

The circuit 18 is designed to produce an output signal whenever its two applied signals are similar, evidencing that the film web 12 is incompatible with the processing which is to be done by the system 10; and attendantly, such output signal, on being applied to an alarm and/or brake 20 will either, or both, alarm a film-processing technician of the problem at hand, or bring the feeding of film web 12 into the processing system 10 to an abrupthalt.

With reference now to FIG. 2, the invention in its presently preferred form provides a pulley 22 comprised of two axially spaced-apart halves 24,26 each supported for rotation by respective bearings 28,30. The two-section pulley thus defines a continuous circumferential slot 27 thereof. The bearing 28 is supported by a housing section 32; and the bearing 30 is supported by a housing section 34.

Also supported by the housing section 32, but contained within a casing 36, is a source 38 of infrared radiation, such casing 36 having a pair of windows 40,42. Electrical power is applied to the radiation source 38 via leads 43. The casing 36 fits, sleevelike, within a slotted squirrel cage member 44, and such member 44 is rotatable by means of a motor 46, whereby the source 38 radiation is modulated, i.e., chopped, at a given frequency. The rotary axis of the squirrel cage member 44 is sufficiently off the rotary axis of the pulley 22 so as to permit a lens 50 to be supported by the housing section 32 between the pulley 22 and the squirrel cage member 44. Thus, modulated radiation from the source 38 (window 40) may be focused through the pulley slot 27 upon a photodetector 52 supported by the housing section 34. A second lens 54, supported by the housing sections 32,34 outside the periphery of the pulley 22,

focuses the source 38 radiation (window 42) upon a photodetector 56 supported by the housing section 34, the lens 54 being disposed distancewise with respect to the window 42 and the photodetector 56 the same as the lens 50 is disposed with respect to its corresponding window 40 and the photodetector 52. Because of such lens dispositions, a pair of balanced optical systems is defined; and such definition occurs even though the two lenses in question are differently situated physically with respect to the pulley 22. As stated above, were it not for the present design, either both lenses would have to reside within a much larger pulley, or both lenses would have to reside outside the pulley; and in either case, the packaging of the device 14 would have to be larger than when packaged in accordance with-the invention.

The photographic film 12 which is to be monitored by use of the invention is adapted to pass over, and rotate, the pulley 22 as such film passes into the film-processing system 10; and the reject reference film strip 16 is adapted to be held fixed in place by means of clips 60 on the housing sections 32,34. Since the two optical systems which have been indicated are effectively identical, identical electrical (alternating) signals will be produced by the chopped light reaching the photodetectors 52,56--provided that the film 12 which is being processed has the same transmission characteristics as the reference film strip 16.

The electrical/output signals from the photodetectors 52,56 are algebraically balanced against each other at a signal summing point 62. Therefore, when the reference and process films are different, a small AC signal-altemating at the chopping frequencyis produced; and such signal is amplified by cascaded amplifiers 64,66. A filter 68, cooperative with the amplifier 64, is tuned to assure that only signals at the chopping frequency are applied to the amplifier 66. Signals appearing at the output of the amplifier 66 are rectified (70), and then applied to cancel a positive bias applied to a potentiometer 73; and signals appearing on the wiper of the potentiometer are adapted to turn on a silicon control rectifier 72, thereby to gate a current through a relay 74 for actuation of an alarm 76 or a similar device. Feedback 78 is provided to stabilize the gain of the amplifier 66.

Operation of the apparatus of FIG. 2 may be best appreciated from a discussion of the setup procedure for such apparatus. Assume that the FIG. 2 apparatus is to monitor the processingof Kodachrome film by Kodachrome processing solutions, with assurance that Ektachrome film will not mistakenly be processed by such solutions: Ektachrome film to be rejected is threaded over the pulley 22 so that infrared radiation exiting from the window 40 passes through such Ektachrome film and falls upon the detector 52; a small setup strip of Ektachrome film is placed within the film clips 60, thereby causing almost no alternating signal to appear at the signal-summing point 62. The wiper of the potentiometer 73 is then so positioned that the potentiometer wiper is just sufficiently positive to gate the silicon control rectifier 72 into conduction. Thereafter, the setup Ektachrome film web which was threaded over the pulley 22 is replaced by a Kodachrome film to be processed, causing the positive potential applied to silicon control rectifier to drop below the gating potential; and so long as Kodachrome film is handled by the Kodachrome processing system, the alarm 76 remains inactive.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

What is claimed is:

1. For use with a system for processing photographic film of a certain type through and by means of processing solutions compatible with said photographic film, apparatus adapted to be disposed at the input of said system, for signalling when film of a type other than said certain type is about to be fed into said system, said apparatus comprising:

a. means for holding a sample of said certain type of film,

b. a source of radiation to which said certain type of film is photographically insensitive,

c. means for directing said source radiation at both the film to be processed and said film sample, and

d. means for comparing the radiation outputs from said film to be processed and from said film sample, and for signalling when the result of such comparison differs from a reference by more than a predetermined amount.

2. The apparatus ofclaim 1 including slotted means enclosing therein said radiation source, said slotted means being adapted for rotation at a predetermined frequency, thereby to chop said light at said frequency, and cause thereby the output of said comparison means to be a signal at said predetermined frequency.

3. The apparatus of claim 2 including means cooperative with said means for comparing radiations for rejecting, from the output of said means for comparing radiations, signals which have frequencies substantially different from said predetermined frequency.

4. The system of claim 2,

a. including a circumferentially slotted pulley over which said film which is to be processed is adapted to pass, and

b. wherein said rotatable slotted means enclosing said source of radiation is so disposed within the periphery of said pulley that said chopped radiation may shine through the film which is adapted to pass over said pulley and through said film sample held by said means for holding said sample.

5. The apparatus of claim 1,

a. wherein said system includes a circumferentially slotted pulley over which said film which is to be processed is adapted to pass,

b. wherein said source of radlatron IS off the rotary axis of said pulley, and

e. wherein said system includes first and second lenses, one lens so disposed within the periphery of said pulley that it directs source radiation via said pulley slot through said film being processed, and said other lens being outside the periphery of said pulley for directing said source radiation through said film sample, both said lenses being substantially equidistant from said radiation source, and being equidistant from the film with which they are respectively cooperative.

6. The apparatus of claim 5 including slotted means enclosing therein said radiation source, said slotted means being adapted for rotation at a predetermined frequency, thereby to chop said light at said frequency, and cause thereby the output of said comparison means to be a signal at said predetermined frequency. 

1. For use with a system for processing photographic film of a certain type through and by means of processing solutions compatible with said photographic film, apparatus adapted to be disposed at the input of said system, for signalling when film of a type other than said certain type is about to be fed into said system, said apparatus comprising: a. means for holding a sample of said certain type of film, b. a source of radiation to which said certain type of film is photographically insensitive, c. means for directing said source radiation at both the film to be processed and said film sample, and d. means for comparing the radiation outputs from said film to be processed and from said film sample, and for signalling when the result of such comparison differs from a reference by more than a predetermined amount.
 2. The apparatus of claim 1 including slotted means enclosing therein said radiation source, said slotted means being adapted for rotation at a predetermined frequency, thereby to chop said light at said frequency, and cause thereby the output of said comparison means to be a signal at said predetermined frequency.
 3. The apparatus of claim 2 including means cooperative with said means for comparing radiations for rejecting, from the output of said means for comparing radiations, signals which have frequencies substantially different from said predetermined frequency.
 4. The system of claim 2, a. including a circumferentially slotted pulley over which said film which is to be processed is adapted to pass, and b. wherein said rotatable slotted means enclosing said source of radiation is so disposed within the periphery of said pulley that said chopped radiation may shine through the film which is adapted to pass over said pulley and through said film sample held by said means for holding said sample.
 5. The apparatus of claim 1, a. wherein said system includes a circumferentially slotted pulley over which said film which is to be processed is adapted to pass, b. wherein said source of radiation is off the rotary axis of said pulley, and c. wherein said system includes first and second lenses, one lens so disposed within the periphery of said pulley that it directs source radiation via said pulley slot through said film being processed, and said other lens being outside the periphery of said pulley for directing said source radiation through said film sample, both said lenses being substantially equidistant from said radiation source, and being equidistant from the film with which they are respectively cooperative.
 6. The apparatus of claim 5 including slotted means enclosing therein said radiation source, said slotted means being adapted for rotation at a predetermined frequency, thereby to chop said light at said frequency, and cause thereby the output of said comparison means to be a signal at said predetermined frequency. 